Quick Answer
The Silver Dollar is a intermediate-level freshwater fish needing at least a 75-gallon tank, 75-82°F water, and pH 5.0-7.0. Silver Dollars require consistent water quality and some experience to keep successfully.
Silver Dollar Overview
The Silver Dollar (Metynnis argenteus) is a rewarding species suited to aquarists with some experience, native to Amazon Basin. As a freshwater herbivore, this species has earned its place as a staple in community tanks, species-only setups, and planted aquariums worldwide. The Silver Dollar is a peaceful species that generally coexists well with other non-aggressive fish. With proper care and appropriate water conditions, Silver Dollars can live for several years and become a rewarding centerpiece — or supporting cast — of your aquarium.
According to FishBase's species profile, the Metynnis argenteus is widely distributed across Amazon Basin and has been selectively bred in captivity for decades, resulting in a robust trade fish that typically adapts well to aquarium conditions. That said, replicating natural water parameters as closely as possible always produces the healthiest fish.
Tank Requirements
The Silver Dollar requires a 75-gallon tank as a minimum — larger is always better. Crowding this species into too-small quarters leads to stress, aggression, and disease — the most common cause of failure with this fish. Budget for a canister filter with adequate flow — target 4–6× tank volume per hour to keep the water clean and well-oxygenated.
- Minimum Tank Size: 75 gallons
- Temperature: 75-82°F (ideal: ~78°F)
- pH: 5.0-7.0 To lower pH toward the 5.0-7.0 range, consider RO/DI water, driftwood, or Indian almond leaves. See our guide on how to lower pH in your aquarium.
- Filtration: A canister filter with adequate flow — target 4–6× tank volume per hour
A fine to medium-grain substrate is appropriate for most specimens, with some species preferring sand or smooth gravel. Once your tank is fully cycled, perform 20–30% water changes weekly to maintain stable parameters. Stability matters more than hitting exact numbers — sudden swings cause far more harm than gradual drift.
Diet & Feeding
The Silver Dollar is a plant-based feeder that grazes throughout the day in its natural habitat. Spirulina flakes, algae wafers, blanched zucchini, cucumber, and nori (dried seaweed sheets) are all excellent choices for this species.
Offer small amounts 2–3 times daily. Herbivores have faster digestive systems and benefit from frequent small meals. Avoid high-protein foods as a primary diet — herbivores that are overfed animal protein can develop digestive issues.
Compatibility & Tank Mates
The Silver Dollar has a peaceful temperament and does well in community aquariums with similarly sized, non-aggressive fish.
Good tank mate options from our database include African Dwarf Frog, Black Phantom Tetra, and Bolivian Ram. Avoid housing Silver Dollars with highly aggressive species or fish that compete for the same territory.
Common Health Issues
The Silver Dollar is susceptible to disease when conditions are suboptimal, but no aquarium fish is immune to illness. Prevention through clean water and a varied diet is always better than treatment. For detailed species-specific health notes, SeriouslyFish has an excellent care sheet for the Silver Dollar.
Ich (White Spot Disease)
The most common freshwater disease — small white spots on fins and body. Raise temperature to 82–86°F and treat with API Super Ich Cure. See our full guide on treating ich.
Fin Rot
Bacterial deterioration of fin tissue, usually caused by poor water quality. Improve water changes, remove organic waste, and treat with Kanaplex or Maracyn if severe.
Velvet (Oodinium)
A parasitic infection causing a gold-dust shimmer on the body. More subtle than ich but equally dangerous. Treat with copper-based medication in a quarantine tank.
Recommended Products
Frequently Asked Questions
What size tank does a Silver Dollar need?
The Silver Dollar requires a minimum of 75 gallons. Smaller tanks cause stress, reduce lifespan, and increase disease susceptibility. If you can afford a larger tank, always go bigger — fish generally thrive with extra space.
What do Silver Dollars eat?
The Silver Dollar is a herbivore. Offer spirulina flakes, algae wafers, blanched vegetables (zucchini, cucumber), and nori sheets. Feed small amounts 2–3 times daily to match their continuous grazing habits.
What water temperature and pH does the Silver Dollar need?
Maintain water temperature between 75-82°F and pH between 5.0-7.0. Use a reliable aquarium thermometer and test your water weekly. Stability is more important than hitting exact numbers — sudden parameter swings are more dangerous than gradual drift.
What fish can live with a Silver Dollar?
The Silver Dollar can coexist with African Dwarf Frog, Black Phantom Tetra, Bolivian Ram, among others with similar temperament and water requirements. Avoid pairing with aggressive fin-nippers or much larger predators.
Is the Silver Dollar suitable for intermediate aquarists?
Yes — the Silver Dollar is a good step up for aquarists moving beyond beginner species. It requires more consistent water quality and some knowledge of the nitrogen cycle, but rewards careful keeping with impressive behavior and appearance.
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